The present invention relates to a two-part seal made of synthetic material for a receptacle containing a free-flowing substance.
More specifically, the present invention relates to a two-part cap device or seal (herein referred to as a cap device or seal) made of synthetic material for a receptacle containing a free-flowing substance, with a lower part that can be slid onto the receptacle and that is in essence rotationally symmetrical around an axis of the cap device, its lower range being equipped with an external thread and an organ for attaching at the receptacle and at a lower and an upper end being provided with one opening each and possessing a non-perforated surface area between these openings, an upper part essentially symmetrical around the axis of the cap device, which in its lower range is provided with an internal thread suited for the external thread and at a lower and an upper end is provided with one opening each and possesses a non-perforated surface area between these openings, a valve pin directed upwards axially at the lower part and held via connecting bars, a valve tube, located axially at the upper part by means of an essentially conical intermediate piece, the internal thread being effectively connected with the external thread in the mounted state of the cap device so that the valve pin may be displaced axially in relation to the valve tube by turning the upper part in relation to the lower part, one cylinder section each located axially at the lower part and at the upper part, and a sealing bulge located at one of the cylinder sections and facing the other cylinder section, the two cylinder sections forming, when the seal is mounted, a tight effective connection by means of the sealing bulge and embracing each other coaxially at least over a part of their lengthwise extension, so that while continuously in a sealing state the two cylinder sections may be displaced axially in relation to each other.
A seal of the kind mentioned at the outset is known from DE-A-3727789 which renders possible a proportioned discharge of the fluid contents of the receptacle. The disadvantage of this seal is the fact that it contains a dead space which is not rinsed by the fluid when it is discharged. Parts of the fluid may remain there for longer periods of time, which cannot be tolerated in particular for fluids of limited storage times, e.g. because of spontaneous solidification or other changes, which may be the case for example with single-package systems, fats, foodstuffs, etc. It is a further disadvantage of this seal that it has a pour-out area where after the fluid discharge has been concluded a fluid residue will remain which then will be exposed to the outside air for an extended period of time. This in turn cannot be tolerated with fluids that will solidify when in contact with the outside air or liable to change in any other way, for example single-package systems which solidify when exposed to air, fats which turn rancid, or foodstuffs which will dry out.
From EP-A-0296103 a seal is known that is equipped with a stopping element that stops up the upper opening of the upper part in the closed state of the seal. This is to prevent the existence of an area where a fluid residue will remain after the fluid discharge has been concluded, which in consequence will be exposed to outside air for longer periods of time. The disadvantage of this system is that after the conclusion of the fluid discharge there will still be a drop of fluid bridging the upper opening of the upper part and the stopping element, especially if the fluid is so viscous that even a big drop may not be removed by shaking it down. The seal according to EP-A-0296103 is dirtied and/or pasted up by this drop. Moreover, the seal according to EP-A-0296103 possesses a dead space which is not rinsed when the fluid is discharged. In addition, the seal according to EP-A-0296103 is equipped with rated break points or flexible parts and thus its production is rather costly.
It is an object of the present invention to create a seal of the kind mentioned at the outset having no dead space which is not rinsed by the fluid when it is discharged and no discharge area which might make possible the remaining of a fluid residue exposed to outside air after the conclusion of the fluid discharge, furthermore which does not allow the formation of a drop bridging the upper opening of the upper part, and which also may be produced at low cost.